Consumers consider tenderness to be the most important component of the meat quality.
The majority of the tenderness problems were improved by post-mortem aging and mechanical
tenderization. The calcium-dependent proteolytic systems, calpains, are responsible for proteolysis of the myofibrilla proteins whose degradation causes the weakening of the myofibrilla structure and, therefore, meat tenderization. One of the primary factors that influence calpain activity in post-mortem muscle is calpastatin activity(Koohmaraie, 1990).